1. Field of the Invention
The present invention relates to an apparatus and method of efficiently producing brick and more specifically relates to an automated low profile dryer, kiln and brick handling system wherein the kiln utilizes a shortened brick firing cycle and requires a minimum of excess or surge brick production.
2. Description of the Prior Art
Virtually all brick production plants in the United States operate in an identical manner. Typically, the brick making machinery is run five days per week for one shift while the kiln and dryer are run continuously. The kilns, which are cosntructed of refractories, must be run around the clock, 365 days per year since intermittent shut down of the kiln will, in most cases, result in damage to the refractory lining. Furthermore, even in those cases where the kiln can be shutdown without damage to the lining, the shutdown cycle (i.e., the time required to safely bring the kiln from operating temperature to ambient temperature) as well as the startup cycle (i.e., the time required to safely bring the kiln from ambient temperature to operating temperature) have both typically been on the order of several days duration.
Thus, in order for the kilns to operate continuously, the production capacity of the brick making equipment must be over four times the throughput of the kiln and dryer so that enough product can be made in a 40 hour work week to satisfy the continuous running of the kiln and dryer. Further, as the unfired (green) brick product accumulates through the week, it must be stored until the time when it is eventually fed to the kiln, such as over weekend periods. Extra kiln cars and extra storage space in the brick producing plants, needed to accomodate the excess unfired brick, add significantly to the overall cost of the plant without providing increased capacity.
Existing brick producing plants have typically required many operators working per shift in order to maintain production. Operators were likewise needed during weekends and holidays due to the continuously running kilns, thereby greatly increasing personnel costs.
In the past, brick producing plants have utilized a kiln firing time on the order of 30-80 hours, depending upon the particular raw material used to make the brick. Such lengthy firing times were necessary due to the amount and manner in which the bricks were passed through the kiln. In most brick producing plants, the bricks are stacked on the deck of a kiln car traveling on tracks through the kiln. An unloaded kiln car has typically had a weight in the range of about 125 to 150 lbs/ft.sup.2 of deck space. Furthermore, the bricks are typically stacked on the kiln car in piles of about 14 bricks high. The brick stacks may have different configurations but typically the bricks are stacked so as to minimize the thickness of the stack, thereby allowing the hot gases in the kiln to more quickly and evenly heat the brick. The brick stacks are typically arranged in rows with rows being separated by a distance of 2 to 6 inches which allows better hot gas circulation resulting in quicker and more even firing of the bricks. Accordingly, the brick loaded kiln car presented an extremely large mass (on the order of 285 to 365 lbs/ft.sup.2) and cross section (of both brick and kiln car) passing through the kiln.